program zdgys1(input,output);
var m,n,r:integer;
begin
  read(m,n);
  if(m<n) then
    begin
      r:=m;m:=n;n:=r;
    end;
  r:=1;
  while r<>0 do
    begin
      r:=m mod n;m:=n;n:=r;
    end;
    writeln(m);
end.